1. Field of the Invention
The present invention relates to an optical waveguide device and a method for connecting an optical waveguide and an optical fiber using the optical waveguide device.
2. Description of the Related Art
In the field of optical communication or optical transmission, various optical devices such as optical switches and optical couplers are used in addition to optical transmitters, optical receivers, and optical transmission lines. As one of the types of such optical devices, there is an optical waveguide device. The optical waveguide device is arranged in such a way that an optical waveguide is formed on a substrate and a light beam is controlled while it is confined in the optical waveguide. Because of its structure, the optical waveguide device has such advantages that it can be easily miniaturized and produced on a mass scale using the planar technique and, in addition, that electric field or magnetic field can be applied thereto effectively. In such optical waveguide devices, it sometimes becomes necessary to connect a plurality of optical fibers with it as is the case with a waveguide type star coupler. Therefore, there have been demands for such an optical waveguide device that can be easily connected with optical fibers.
In connecting an optical waveguide device and optical fibers, it has so far been practiced to adjust position of the optical fibers relative to input and output terminals of the optical waveguide device individually and, then, to fix the optical fibers to the input and output terminals of the optical waveguide device with an optical bonding agent having a desired refractive index. This connecting method, however, takes much time in adjusting position of the optical fibers and involves a problem that troublesome work is required for connecting the optical waveguide device with optical fibers.
There is proposed a method to connect an optical fiber to an optical waveguide device in which a groove or a pair of projections are formed on the substrate of the optical waveguide device and the optical fiber is mounted in the groove or between the pair of projections, and connection is thereby achieved without making positioning adjustments of the optical fiber. According to this connecting method, while the need for positioning adjustments of the optical fiber can be eliminated, there is a problem that the groove or the pair of projections must be made with high precision in order to achieve a low-loss optical connection.